Metal tube



No. 624,|44. Patented May. 2, I899.

E..A.f*-WlliMOT.

METAL TUBE.

(Application filed Jan. 27, 1899.) (N o M ed el WITNESSES INVENTOR fivi.f v M? ms PEYgns 00,. PHoTo-umuu WASHINGTON u.

'ATENT FRANK A. WILMOT, OF BRIDGEPORT, CONNECTICUT.

M ETAL TIUBE.

SPECIFICATION forming part of Letters Patent No. 624,144, dated May 2,1899'.

Application filed January 27, 1899- Serial No. 703,590. kNo model.)

To all whom it may concern:

Be it known that I, FRANK A. WILMOT, a citizen of the UnitedStates,residing at Bridgeport, county of Fairfield, State ofConnecticut, have invented a new and useful Metal Tube, (Case 13,) ofwhich the following is a specification.

Myinvention relates to metal tubing adapted for general use, andespecially adapted for use in the manufacture of bicycle-frames,bayonet-scabbards, and other articles formed from iron or steel tubing,it not being essential, so far as the principle of my'invention isconcerned, that the tubing be produced in any special manner.as, forexample, in carrying out my invention the tubing may be ordinary drawntubing or jointed tubing of any ordinary grade, or it may be tubing ofthe kind known to the trade as clencher tubingthat is, tubing formedfrom a strip of sheet metal having upon its edges interlockingprojections and recesses, said edges being closed together bycircumferential compression, so that in certain of the teeth metal isdisplaced laterally in alternate opposite directions, causing the teethon the opposite edges to clench firmly, as fully set forth and claimedin Letters Patent Nos. 578,799, 578,800, and 578,801, granted to meMarch 16, 1897; and my present invention has for its object to produce atube of this character which shall be moisture-proof from the inside,Water-tight at the joint, which will take the solder readily in brazingflush joints, and which will take an enamel upon its outer side and holdit so that blistering shall be prevented.

In the accompanying drawings, forming part of this specification, Figurel is a perspective illustrating my novel tubing in the process ofmanufacture, the tube having been dipped and being covered interiorlyand exteriorly with a coating of non-oxidizable metal; Fig. 2, a similarview illustrating the operation of grinding off the outer coating; Fig.3, an end View, on an enlarged scale, illustrating the tube as in Fig.1that is, after being dipped or otherwise coated interiorly andexteriorly with non-oxidizable metal; Fig. 4, a similar viewillustrating the completed tube-that is to say, the outer coating ofnon-oxidizable metal having been ground off in order to finish the tubeand the joint, the joint, in fact, being barely visible in the tubing asfinished for shipment or use; and Figs. 5 and 6 are perspectivesillustrating the principle of my invention as applied in connection withflat-sided tubing and illustrating different well-known styles ofinterlocking joints and also showing tubes made from a plurality ofpieces or strips of metal' that is, having a plurality of joints.

It "is of course well understood that in the manufacture ofbicycle-frames it is found practicallyimpossiblein assembling the partsto prevent moisture from getting into the tubes. It has been a seriousobjection to all classes of tubingheretofore used in the manufacture ofbicycle-frames that moisture within the tubes would cause oxidation ofthe tubes from the innerside, frequently causing the enamel to blisterand flake off and sometimes completely destroying the integrity of thetubing, so'that the'bicycle .became liable to break in use, with seriousresults to the rider. This objection I wholly overcome by dipping thetubes,without anypolishing orfin ishing whateveigin asuitable moltennon-oxidizable metal or alloy-for example, brass whereby a coating ofthe non-oxidizable metal is formed both on the interior and exterior ofthe tubes. Other import-ant advantages which result from dipping thetubes in molten non-oxidizable metal or alloy are that the intersticesof the joint are completely filled with the molten metal, which soldersthe joint in the most effective manner possible'and makes the tubes forall practical purposes solid tubes. Another advantage is that the innercoating of non-oxidizable metal makes a perfect preparation without anyadditional operations for brazing flush joints, as in putting the partsof a bicycle-frame together, and another very important advantage isthat the cost of final grinding of the tube is found to be greatlyreduced by the coating of non-oxidizable metal, which is ground oif inthe manner that a tube is ordinarily ground for the purpose ofpolishing; but it is found in practice that when coated with anothermetal a very fine finish may be produced upon the tubes by grinding muchmore easily and quickly than if the tubes are ground without dipping inmolten metal. V

A denotes the tube, which may be of iron or steel and may be a drawntube or a jointed tube of any style, although I preferably use in makingmy novel tubing steel tubes of the well-known clencher type-that is,tubes formed from blanks or strips of sheet metal having upon theiredges interlocking projections and recesses, said edges being closedtogether by circumferential compression,so that in certain of the teethmetal is displaced laterally in alternate opposite directions, cansin gthe teeth on the opposite edges to cleneh firmly. It will of course beapparent that the tubes may be formed from a plurality of pieces orstrips of metal and of any desired form in cross-section. B denotes aninner coating of any suitable non-oxidizable metal or alloy, whichcomprises part of the finished tubing, and C an outer coating of thesame metal, which is placed upon the tube simultaneously with the innercoating, preferably by dipping the entire tube in molten metal or alloy,but which is wholly ground off in the final process of polishing andfinishing the tube forshipment or use,it beingof course understood thattubing of this character after being manufactured into articles, asbicycles, is ordinarily finished exteriorly by japanning of the qualitycommonly known as enameling and that this finish requires that the ironor steel tubes upon which it is placed should be thoroughly cleaned andpolished. The grinding or polishing of the tubes may be effected in anypreferred manner, as by a grinding-wheel D.

It is to be understood that owing to the fact that the tube isbutt-jointed in the sense that its edges do not overlap each other, butabut against each other, and that the joint is flushed with thenon-oxidizable metal or alloy by being dipped therein the subsequentgrinding of the outer surface leaves said joint absolutelyimperceptible.

Having thus described my invention, I claim 1. The method of finishingmetal tubing which consists in coating the tubes both interiorly andexteriorly with a non-oxidizable metal or alloy and then grinding offthe coating from the exterior of the tubes, substantially as and for thepurposes set forth.

2. The method of finishing sheet-metal tubing which consists in dippingthe tubes in molten non-oxidizable metal or alloy whereby anon-oxidizable metallic coating is formed interiorly and exteriorly ofthe tubes and then finishing the tubes by grinding oif the coating fromthe exterior thereof.

3. The method of making and finishing sheet-metal tubing which consistsin providing each edge of a blank of sheet metal with a series ofinterlocking projections and recesses, then closing said edges together,then dipping the tube in molten non-oxidizable metal or alloy wherebythe interstices of the joint are filled and the edges are solderedtightly together and then finishing the tube by grinding off the coatingfrom the exterior thereof.

4. The method of making and finishing sheet-metal tubing which consistsin providing each edge of a blank of sheet metal with a series ofinterlocking projections and recesses, then closing said edges togetherby circumferential compression so that metal of certain of the teeth isdisplaced laterally in alternate opposite directions then dipping thetube in molten non-oxidizable metal or alloy whereby the interstices ofthe joint are filled and the edges are soldered tightly together andthen finishing the tube by grinding off the coating from the exteriorthereof.

5. As a new manufacture, a butt-jointed iron or steel tube dipped in anon-oxidizable metal or alloy and having its outer surface groundsmooth.

(5. A tube formed from a blank of sheet metal having upon its edgesinterlocking pro-

